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/*
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 * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
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 *    this list of conditions and the following disclaimer.
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package java.time;

import static java.time.temporal.ChronoField.DAY_OF_WEEK;
import static java.time.temporal.ChronoUnit.DAYS;

import java.time.format.DateTimeFormatterBuilder;
import java.time.format.TextStyle;
import java.time.temporal.ChronoField;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalQuery;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.time.temporal.ValueRange;
import java.time.temporal.WeekFields;
import java.util.Locale;

/**
 * A day-of-week, such as 'Tuesday'.
 * <p>
 * {@code DayOfWeek} is an enum representing the 7 days of the week -
 * Monday, Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday.
 * <p>
 * In addition to the textual enum name, each day-of-week has an {@code int} value.
 * The {@code int} value follows the ISO-8601 standard, from 1 (Monday) to 7 (Sunday).
 * It is recommended that applications use the enum rather than the {@code int} value
 * to ensure code clarity.
 * <p>
 * This enum provides access to the localized textual form of the day-of-week.
 * Some locales also assign different numeric values to the days, declaring
 * Sunday to have the value 1, however this class provides no support for this.
 * See {@link WeekFields} for localized week-numbering.
 * <p>
 * <b>Do not use {@code ordinal()} to obtain the numeric representation of {@code DayOfWeek}.
 * Use {@code getValue()} instead.</b>
 * <p>
 * This enum represents a common concept that is found in many calendar systems.
 * As such, this enum may be used by any calendar system that has the day-of-week
 * concept defined exactly equivalent to the ISO calendar system.
 *
 * @implSpec This is an immutable and thread-safe enum.
 * @since 1.8
 */
public enum DayOfWeek implements TemporalAccessor, TemporalAdjuster {

  /**
   * The singleton instance for the day-of-week of Monday.
   * This has the numeric value of {@code 1}.
   */
  MONDAY,
  /**
   * The singleton instance for the day-of-week of Tuesday.
   * This has the numeric value of {@code 2}.
   */
  TUESDAY,
  /**
   * The singleton instance for the day-of-week of Wednesday.
   * This has the numeric value of {@code 3}.
   */
  WEDNESDAY,
  /**
   * The singleton instance for the day-of-week of Thursday.
   * This has the numeric value of {@code 4}.
   */
  THURSDAY,
  /**
   * The singleton instance for the day-of-week of Friday.
   * This has the numeric value of {@code 5}.
   */
  FRIDAY,
  /**
   * The singleton instance for the day-of-week of Saturday.
   * This has the numeric value of {@code 6}.
   */
  SATURDAY,
  /**
   * The singleton instance for the day-of-week of Sunday.
   * This has the numeric value of {@code 7}.
   */
  SUNDAY;
  /**
   * Private cache of all the constants.
   */
  private static final DayOfWeek[] ENUMS = DayOfWeek.values();

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code DayOfWeek} from an {@code int} value.
   * <p>
   * {@code DayOfWeek} is an enum representing the 7 days of the week.
   * This factory allows the enum to be obtained from the {@code int} value.
   * The {@code int} value follows the ISO-8601 standard, from 1 (Monday) to 7 (Sunday).
   *
   * @param dayOfWeek the day-of-week to represent, from 1 (Monday) to 7 (Sunday)
   * @return the day-of-week singleton, not null
   * @throws DateTimeException if the day-of-week is invalid
   */
  public static DayOfWeek of(int dayOfWeek) {
    if (dayOfWeek < 1 || dayOfWeek > 7) {
      throw new DateTimeException("Invalid value for DayOfWeek: " + dayOfWeek);
    }
    return ENUMS[dayOfWeek - 1];
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code DayOfWeek} from a temporal object.
   * <p>
   * This obtains a day-of-week based on the specified temporal.
   * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
   * which this factory converts to an instance of {@code DayOfWeek}.
   * <p>
   * The conversion extracts the {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} field.
   * <p>
   * This method matches the signature of the functional interface {@link TemporalQuery}
   * allowing it to be used as a query via method reference, {@code DayOfWeek::from}.
   *
   * @param temporal the temporal object to convert, not null
   * @return the day-of-week, not null
   * @throws DateTimeException if unable to convert to a {@code DayOfWeek}
   */
  public static DayOfWeek from(TemporalAccessor temporal) {
    if (temporal instanceof DayOfWeek) {
      return (DayOfWeek) temporal;
    }
    try {
      return of(temporal.get(DAY_OF_WEEK));
    } catch (DateTimeException ex) {
      throw new DateTimeException("Unable to obtain DayOfWeek from TemporalAccessor: " +
          temporal + " of type " + temporal.getClass().getName(), ex);
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the day-of-week {@code int} value.
   * <p>
   * The values are numbered following the ISO-8601 standard, from 1 (Monday) to 7 (Sunday).
   * See {@link java.time.temporal.WeekFields#dayOfWeek()} for localized week-numbering.
   *
   * @return the day-of-week, from 1 (Monday) to 7 (Sunday)
   */
  public int getValue() {
    return ordinal() + 1;
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the textual representation, such as 'Mon' or 'Friday'.
   * <p>
   * This returns the textual name used to identify the day-of-week,
   * suitable for presentation to the user.
   * The parameters control the style of the returned text and the locale.
   * <p>
   * If no textual mapping is found then the {@link #getValue() numeric value} is returned.
   *
   * @param style the length of the text required, not null
   * @param locale the locale to use, not null
   * @return the text value of the day-of-week, not null
   */
  public String getDisplayName(TextStyle style, Locale locale) {
    return new DateTimeFormatterBuilder().appendText(DAY_OF_WEEK, style).toFormatter(locale)
        .format(this);
  }

  //-----------------------------------------------------------------------

  /**
   * Checks if the specified field is supported.
   * <p>
   * This checks if this day-of-week can be queried for the specified field.
   * If false, then calling the {@link #range(TemporalField) range} and
   * {@link #get(TemporalField) get} methods will throw an exception.
   * <p>
   * If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then
   * this method returns true.
   * All other {@code ChronoField} instances will return false.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
   * passing {@code this} as the argument.
   * Whether the field is supported is determined by the field.
   *
   * @param field the field to check, null returns false
   * @return true if the field is supported on this day-of-week, false if not
   */
  @Override
  public boolean isSupported(TemporalField field) {
    if (field instanceof ChronoField) {
      return field == DAY_OF_WEEK;
    }
    return field != null && field.isSupportedBy(this);
  }

  /**
   * Gets the range of valid values for the specified field.
   * <p>
   * The range object expresses the minimum and maximum valid values for a field.
   * This day-of-week is used to enhance the accuracy of the returned range.
   * If it is not possible to return the range, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the
   * range of the day-of-week, from 1 to 7, will be returned.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
   * passing {@code this} as the argument.
   * Whether the range can be obtained is determined by the field.
   *
   * @param field the field to query the range for, not null
   * @return the range of valid values for the field, not null
   * @throws DateTimeException if the range for the field cannot be obtained
   * @throws UnsupportedTemporalTypeException if the field is not supported
   */
  @Override
  public ValueRange range(TemporalField field) {
    if (field == DAY_OF_WEEK) {
      return field.range();
    }
    return TemporalAccessor.super.range(field);
  }

  /**
   * Gets the value of the specified field from this day-of-week as an {@code int}.
   * <p>
   * This queries this day-of-week for the value of the specified field.
   * The returned value will always be within the valid range of values for the field.
   * If it is not possible to return the value, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the
   * value of the day-of-week, from 1 to 7, will be returned.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
   * passing {@code this} as the argument. Whether the value can be obtained,
   * and what the value represents, is determined by the field.
   *
   * @param field the field to get, not null
   * @return the value for the field, within the valid range of values
   * @throws DateTimeException if a value for the field cannot be obtained or the value is outside
   * the range of valid values for the field
   * @throws UnsupportedTemporalTypeException if the field is not supported or the range of values
   * exceeds an {@code int}
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public int get(TemporalField field) {
    if (field == DAY_OF_WEEK) {
      return getValue();
    }
    return TemporalAccessor.super.get(field);
  }

  /**
   * Gets the value of the specified field from this day-of-week as a {@code long}.
   * <p>
   * This queries this day-of-week for the value of the specified field.
   * If it is not possible to return the value, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the
   * value of the day-of-week, from 1 to 7, will be returned.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
   * passing {@code this} as the argument. Whether the value can be obtained,
   * and what the value represents, is determined by the field.
   *
   * @param field the field to get, not null
   * @return the value for the field
   * @throws DateTimeException if a value for the field cannot be obtained
   * @throws UnsupportedTemporalTypeException if the field is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public long getLong(TemporalField field) {
    if (field == DAY_OF_WEEK) {
      return getValue();
    } else if (field instanceof ChronoField) {
      throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
    }
    return field.getFrom(this);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns the day-of-week that is the specified number of days after this one.
   * <p>
   * The calculation rolls around the end of the week from Sunday to Monday.
   * The specified period may be negative.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param days the days to add, positive or negative
   * @return the resulting day-of-week, not null
   */
  public DayOfWeek plus(long days) {
    int amount = (int) (days % 7);
    return ENUMS[(ordinal() + (amount + 7)) % 7];
  }

  /**
   * Returns the day-of-week that is the specified number of days before this one.
   * <p>
   * The calculation rolls around the start of the year from Monday to Sunday.
   * The specified period may be negative.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param days the days to subtract, positive or negative
   * @return the resulting day-of-week, not null
   */
  public DayOfWeek minus(long days) {
    return plus(-(days % 7));
  }

  //-----------------------------------------------------------------------

  /**
   * Queries this day-of-week using the specified query.
   * <p>
   * This queries this day-of-week using the specified query strategy object.
   * The {@code TemporalQuery} object defines the logic to be used to
   * obtain the result. Read the documentation of the query to understand
   * what the result of this method will be.
   * <p>
   * The result of this method is obtained by invoking the
   * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
   * specified query passing {@code this} as the argument.
   *
   * @param <R> the type of the result
   * @param query the query to invoke, not null
   * @return the query result, null may be returned (defined by the query)
   * @throws DateTimeException if unable to query (defined by the query)
   * @throws ArithmeticException if numeric overflow occurs (defined by the query)
   */
  @SuppressWarnings("unchecked")
  @Override
  public <R> R query(TemporalQuery<R> query) {
    if (query == TemporalQueries.precision()) {
      return (R) DAYS;
    }
    return TemporalAccessor.super.query(query);
  }

  /**
   * Adjusts the specified temporal object to have this day-of-week.
   * <p>
   * This returns a temporal object of the same observable type as the input
   * with the day-of-week changed to be the same as this.
   * <p>
   * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
   * passing {@link ChronoField#DAY_OF_WEEK} as the field.
   * Note that this adjusts forwards or backwards within a Monday to Sunday week.
   * See {@link java.time.temporal.WeekFields#dayOfWeek()} for localized week start days.
   * See {@code TemporalAdjuster} for other adjusters with more control,
   * such as {@code next(MONDAY)}.
   * <p>
   * In most cases, it is clearer to reverse the calling pattern by using
   * {@link Temporal#with(TemporalAdjuster)}:
   * <pre>
   *   // these two lines are equivalent, but the second approach is recommended
   *   temporal = thisDayOfWeek.adjustInto(temporal);
   *   temporal = temporal.with(thisDayOfWeek);
   * </pre>
   * <p>
   * For example, given a date that is a Wednesday, the following are output:
   * <pre>
   *   dateOnWed.with(MONDAY);     // two days earlier
   *   dateOnWed.with(TUESDAY);    // one day earlier
   *   dateOnWed.with(WEDNESDAY);  // same date
   *   dateOnWed.with(THURSDAY);   // one day later
   *   dateOnWed.with(FRIDAY);     // two days later
   *   dateOnWed.with(SATURDAY);   // three days later
   *   dateOnWed.with(SUNDAY);     // four days later
   * </pre>
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param temporal the target object to be adjusted, not null
   * @return the adjusted object, not null
   * @throws DateTimeException if unable to make the adjustment
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public Temporal adjustInto(Temporal temporal) {
    return temporal.with(DAY_OF_WEEK, getValue());
  }

}
